Continuous process and apparatus for separating hydrocarbons from earth particles and sand

ABSTRACT

Earth and sand containing bitumen, tar, and/or oil is broken down to particle sizes that can be suspended in water as a carrier for the particles, so that the suspension can be pumped upwardly through an inclined duct or separator where the suspended particles are subjected to horizontal ultrasonic vibrations of between about 18 and 27 kiloHertz for a period between about 5 and 10 minutes. These vibrations completely separate the hydrocarbons from the earth and sand, and entrap gases in the heavier-than-water hydrocarbons so that all the hydrocarbons float to the top of the duct or ultrasonic separator to form a layer which can easily be withdrawn. The cleaned earth and solid particles settle behind a baffled and perforated partition along and above the lower side of the duct or unit, from which lower side these cleaned particles can be removed. The water carrier is withdrawn near the upper end of the separator below the hydrocarbon layer, and recirculated to the lower end of the separator for suspending more hydrocarbon-containing particles.

This is a division of application Ser. No. 06/213,956 filed Dec. 8, 1980now U.S. Pat. No. 4,358,373 issued Nov. 9, 1982.

BACKGROUND OF THE INVENTION

Ultrasonic treatment of aqueous suspensions for the removal of organicmaterials including bitumens from oil sands are known, but none of theknown processes employ the applicant's above combination of steps andconditions. Some of the most pertinent patents disclosing this prior artare:

    ______________________________________                                        Bodine       3,123,546 Mar. 3, 1964                                                                              208-11                                     Bodine, Jr.  Canadian  May 25, 1965                                                                              166-26                                                    710,135                                                        Bodine       3,189,536 June 15, 1965                                                                             208-11                                     Williams     Canadian  Apr. 4, 1967                                                                              196-11                                                    756,078                                                        Pelopsky et al                                                                             3,497,005 Feb. 24, 1970                                                                             166-247                                    Felix et al  Canadian  Dec. 19, 1972                                                                             166-26                                                    917,103                                                        Halloway et al                                                                             3,849,196 Nov. 19, 1974                                                                             134-1                                      Baswick      Canadian  Sept. 7, 1976                                                                             196-30                                                    996,485                                                        Fisher et al 4,049,053 Sept. 20, 1977                                                                            166-249                                    Ducote       4,062,696 Dec. 13, 1977                                                                             134-1                                      Wallace      4,118,282 Oct. 3, 1978                                                                              201-2.5                                    Vermeulen et al                                                                            4,136,014 Jan. 23, 1979                                                                             208-11                                     Grow         4,151,067 Apr. 24, 1979                                                                             208-11                                     ______________________________________                                    

The sonic treatment of suspensions with aeration is also known as shownby the following patents:

    ______________________________________                                        Sasaki     2,907,455  Oct. 6, 1959 209-5                                      Weston     3,202,281  Aug. 24, 1965                                                                              209-166                                    Wohlert    4,045,243  Aug. 30, 1977                                                                              134-1                                      ______________________________________                                    

The previous most successful sonic treatment of particles containingbitumen and oil has been by suspending the particles in a solvent orwith an additive. Such processes have the disadvantage of involvingchemical disposal problems and the requirement of a continuous supply ofchemicals. Applicant's invention does not employ any chemicals includingsolvents in his separation process. However, some of these sonictreating solvent and/or chemical added processes are disclosed in thefollowing patents:

    ______________________________________                                        Morrell et al                                                                            2,722,498   Nov. 1, 1955                                                                              196-14                                     Logan      2,973,312   Feb. 28, 1961                                                                             208-11                                     Bulat      Canadian    Dec. 19, 1961                                                                             208-8                                                   633,063                                                          Bulat et al                                                                              3,017,342   Jan. 16, 1962                                                                             208-11                                     Duff       Canadian    May 3, 1966 196-11                                                  733,481                                                          Hart Jr. et al                                                                           4,054,505   Oct. 18, 1977                                                                             208-11                                     Hart Jr. et al                                                                           4,054,506   Oct. 18, 1977                                                                             208-11                                     ______________________________________                                    

Agitation together with aeration of particles is also known, but notagitation at ultrasonic frequencies, which processes are disclosed inthe following patents:

    ______________________________________                                        Eyre      2,790,750   Apr. 30, 1957                                                                            196-1                                        Clark     Canadian    Dec. 28, 1971                                                                            196-11                                                   889,284                                                           Evans et al                                                                             Canadian    Jan. 2, 1973                                                                             196-30                                                   918,091                                                           Schutte   3,869,384   Mar. 4, 1975                                                                             210-44                                       ______________________________________                                    

Also agitation in hot water for treating suspensions for the removal oforganic compounds is also known from the following patents:

    ______________________________________                                        Camp     Canadian     June 29, 1971                                                                            196-11                                                  874,418                                                            Maloney  Canadian     Feb.3, 1976                                                                              196-24                                                  982,966                                                            Bain et al                                                                             4,018,664    Apr. 19, 1977                                                                            208-11                                       ______________________________________                                    

Thus, although many of the separate features of applicant's inventionare known in the prior art as mentioned above, there is no knowncontinuous process and/or apparatus therefor which employs applicant'sspecific combination of relatively low ultrasonic frequencies andexposing such frequencies to the particles to be separated for such arelatively long period of time. Some known specific apparati forseparation of suspensions containing organic material are listed below:

    ______________________________________                                        Coulson et al                                                                              2,885,339 May 5, 1959 208-11                                     Clem         2,550,776 May 1, 1951 92-44                                      Eyre         2,790,750 Apr. 30, 1957                                                                             196-1                                      Logan        2,973,312 Feb. 28, 1961                                                                             208-11                                     Bodine       3,189,536 June 15, 1965                                                                             208-11                                     Williams     Canadian  Apr. 4, 1967                                                                              196-11                                                    756,078                                                        Halloway et al                                                                             3,849,196 Nov. 19, 1974                                                                             134-1                                      ______________________________________                                    

SUMMARY OF THE INVENTION

The process for the separation of bitumens, tars and oil or hydrocarbonsfrom earth and sands according to the process of this invention is alsoadaptable for the removal of oil from shales and of bitumens fromtailings from oil sand separation processes where there still is 2% or3% of bitumen left on the sands, and also for the recovery of oil fromspent lubricating oils used in engines, and the like.

The particles from which the hydrocarbons are to be separated are brokensuch as by rollers to a size less than about two centimeters in diameterand preferably less than about one-half centimeter and much smaller sothat they can be suspended easily in water as an aqueous carrier forthese particles, and so that the suspension can be pumped easily. Thissuspension contains at least about 50% by weight water.

The suspension is pumped upwardly through an inclined duct of anultrasonic separator at an angle which may vary from 1° or 2° to 90°,but most generally at an angle between about 25° and 30°. This inclinedduct or separator has a longitudinal apertured partition spaced aboveits lower or bottom wall so as to form two parallel duct sections orchambers in the separator, one above the other; the upper chamber orsection being the larger and having alternately located along itsvertical parallel sides ultrasonic transducers for vibrating theparticles in the suspension to remove the hydrocarbons therefrom. Thisupper chamber or section communicates with the lower chamber or sectionby a plurality of transverse slots covered by baffles angled upwardly inthe direction of flow of the suspension, which slots permit the heavierearth and sand particles to settle under the baffles into the lowersection for removal at spaced intervals along the lower side or bottomwall of the separator. Thus the suspension is pumped and flows upwardlythrough the larger duct section of the ultrasonic separator.

In order to obtain sufficient dwell time or exposure of between about 5and 10 minutes for the particles to the ultrasonic vibrations, theseparator may have to be quite long if a relatively high flow rate isemployed. Such a long separator may be made less cumbersome by dividingit into a series of overlapping parallel inclined ultrasonic separatorunits with the top end of one unit connected by a pipe to the bottom endof the next unit. Thus there may be as many as five more or less unitsin a given plant. The solid particles may be removed from the lower endsof the lower sections of each unit, but usually not at the bottom of thefirst or second unit because the flow of the suspension up through theunits carries with it the earth and sand particles until they have beenvibrated for at least about 5 minutes and preferably about 6 to 8minutes, to be completely separated from their bituminous coatings. Thisrelatively long ultrasonic vibration treating time produces cavitationof gases in the bitumen particles which are more dense than water tomake them more buoyant, causing them to float to the top of the lastseparator unit and form an easily decantable layer with the otherhydrocarbons removed from the earth and sand particles.

The water carrier is also removed from the last separator unit below theaccumulated hydrocarbon layer and recycled into a spray mixing chamberfor the suspension of the particles to be introduced into the ultrasonicseparator unit. If desired, this water can be passed through a heatexchanger where the temperature thereof may be raised up to about 90° C.and usually between about 75° and 80° C. to aid in the separation ofcertain types of hydrocarbons impregnating inorganic or heavier solids.

If desired, the decanted or removed hydrocarbon layer may be transferredto a mixing tank and chemicals added thereto if it is too viscous foreasy pumping or transport.

The sediments of earth, oil and sand which collect below the baffles inthe ultrasonic separating unit may be continuously removed from near thebottom of these units from the lower duct sections therein, withrelatively little water, so that they can be directly returned to theearth as clean particles uncontaminated with any chemicals, thus notonly preserving but improving the environment from whence they wereoriginally taken as being contaminated with hydrocarbons. In fact, thetailing ponds from previous hot water oil sand separation processes canbe supplied with a barge having thereon the apparatus for the process ofthis invention, which could continuously rework these tailings torecover more hydrocarbons from them that cannot be or were not removedby the previous hot water or steam treating process.

OBJECTS AND ADVANTAGES

Accordingly, it is an object of this invention to produce a simple,economic, efficient, effective, continuous, and self-containing processand apparatus for removing bitumens, tars and oils from inorganic solidparticles such as earth and sand.

Another object is to provide such a separation process which overcomesthe difficulties and problems of known prior art processes.

Another object is to produce such a process in which no solvents orchemicals are needed for the separation and thereby no contamination orpollution of the environment occurs since no disposal problems areinvolved.

Another object is to produce such a process in which only water is usedas a carrier, which water is cleaned, reused and/or recycled and therebythis process can be used in places where water is not abundant.

Another object is to produce a continuous process which completelyseparates all organic materials and/or hydrocarbons such as bitumens,oils and tars from emulsions, soils, earth and sands, permitting theparticles to be returned directly to the environment cleaner than theywere removed.

Another object is to produce a process and apparatus whereby thetailings of previous oil-removing processes for oil sands can be furthertreated to recover more hydrocarbons.

Another object is to produce a process whereby even the bituminousproducts which are heavier than water can be caused to float in thewater suspension by producing gaseous cavitation in these bituminousproducts.

BRIEF DESCRIPTION OF THE DRAWINGS

The above mentioned and other features, objects and advantages, and amanner of attaining them are described more specifically below byreference to an embodiment of the invention shown in the accompanyingdrawings wherein:

FIG. I is a schematic flow diagram of the process according to apreferred embodiment of this invention;

FIG. II is an enlarged detailed view of the side of a portion of one ofthe ultrasonic separator units shown in FIG. I with a part thereofbroken away;

FIG. III is a plan view of the section of the separator unit shown inFIG. II with its top wall broken away.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS A. Process

Referring first to FIG. I, there is disclosed a schematic flow diagramof a process of this invention for the separation of bitumen from tarsand tailings, which process could be mounted on a barge floated in thepond of the tailings. This barge could dredge up the tailings at its oneend, process them, and discharge the clean sands and earth particlesfrom its other end. It could employ only the water in the pond as thecarrier for the tailings through the apparatus of the process.

More specifically, the tar sand tailings may be introduced from aconveyor 10 into a spray hopper 12 which may comprise a plurality ofcentral water spray nozzles 14 for water from a pump 16 under sufficientpressure to insure that the tailings are broken into small enough sizeto be suspended in the water. The pressurized water spray may be heatedto a temperaure below its boiling point, preferably less than about 95°C., and usually to between about 70° and 80° C. The resulting suspensionis then pumped from duct 18 by a pump 20 into the ultrasonic separatorunits 22 through 26, successively, which comprise specifically designedducts as disclosed in FIGS. II and III and described in Section B below.These inclined ducts may be set at an angle alpha (α) which may varyfrom 1° or 2° up to 90°, but preferably between about 25° and 30° asthose shown in FIG. I. These ducts are successively connected togetherthrough pipes 32, 33, 34, 35 and 36, respectively.

In order to control the flow and the time of the contact of theparticles suspended in the water in the ultrasonic separator orseparator units 22-26, there may be provided a valve bypass duct 21around the pump 20. These ultrasonic separator units 22 through 26 areeach provided along their opposite parallel vertical sides alternatelywith ultrasonic transducers so that the liquid or water carrying insuspension the particles to be separated are continuously exposed,transversely to their direction of flow, to horizontal vibrationsbetween the range of about 18 and 27 kiloHertz per second, andpreferably about 20 to 25 kiloHertz, for a time of at least five andless than about ten minutes, and preferably between about six and eightminutes. This relatively long treatment at a relatively low ultrasonicfrequency not only completely removes all of the organic material orhydrocarbons, such as bitumens, tars, and oil, still clinging onto thetailings, but also produces by cavitation gas entrained in the heavierbitumen particles so as they will become less dense than water and floatto the top of the last separator unit 26 for removal into an oil mixingtank 50 through the duct 51 with the other removed hydrocarbons that areless dense than water. This tank 50 may have a partition 52 and may havefed therein a chemical or solvent through valved duct 54 to treat anyremoved tars or bitumens which are too viscous to flow easily throughthe outlet duct 56.

The clean solids, sediments, sand and earth particles heavier than thewater settle mostly in the last separator units 24, 25 and 26, whichseparator units are divided longitudinally by partitions with baffledslots or apertures so that these solid particles can escape throughthese slots from the current flow of the water carrier through theunits, and can settle near the bottoms of the units below thepartitions, and can readily be drawn off, even continuously, through thevalved pipes 44, 45 and 46 and discharged into a common manifold 47 fordeposit upon a conveyor 48 for return to the environment as clean,uncontaminated and unpolluted earth and sand. Although each of theultrasonic separating units 22 through 26 are provided along their fulllengths with ultrasonic transducers, only the latter may be providedwith the longitudinal partition or baffles for separating the cleanedinorganic solid particles. However, such partitions may be provided inall of the units 22 through 26, as desired, and the sand may be removedfrom each one of them as is shown for the ducts 44 through 46 on thelast three units 24 through 26.

The water used as the carrier is removed from the last ultrasonicseparator unit 26 near its upper end but below the level of the floatinghydrocarbons via a pipe 57 and is pumped by pump 58 and pipe 59 to awater heater 60 having a steam coil 62 wherein the water may be raisedto the temperature previously described for introduction into the sprayunit 12. Make-up water can be introduced into this tank 60 via valvedpipe 64, and the withdrawal of the heated water is through duct 66 topressure pump 16.

The heat or steam supply for heating the coil 62 and the water in thetank 60 may be provided from a low-pressure boiler which may be heatedby the oil recovered from the process of this invention. Thus theprocess is self-contained. The only large quantity additive being water,which is recycled through the process, and originally may be obtainedfrom the pond upon which the barge of the apparatus floats.

B. The Apparatus

Referring to FIGS. II and III there is shown a portion of one of theultrasonic separator units 22 through 26, such as the lower end of unit24, in which the duct 240 is provided with two vertical parallel sidewalls 241 and 242, a top wall 243, a bottom wall 244, and anintermediate perforated or slotted partition wall 245 parallel to thetop and bottom walls and spaced between about one-fourth and one-thirdof the distance between the top and bottom walls from the bottom wall244. Since all of the separators 22 through 26 are the same throughouttheir lengths, FIGS. II and III are representative of sections takenanywhere along any of them. The slots 246 regularly spaced along thelength of the partition wall 245 and transverse thereof, are covered byupwardly angular baffles 247 angled in the direction of flow of theaqueous suspension through the duct as indicated by the arrows 248 sothat the flow of the liquid upwardly through the duct at the angle αwill not easily flow back and downwardly through the slots 246, butpermit the separated solids to settle beneath the baffles 247 and flowdown through the slots 246 and collect in the lower smaller chamber ofthe duct 240 between the partition 245 and bottom wall 244, where theymay be intermittently or continuously removed through the duct 44. Thesebaffles 247 preferably are hinged at 251 and ganged together so thatthey can be adjusted to compensate for different rates of settlingparticles.

Alternately on opposite sides of the duct or separator unit 240, inapertures 249 in the side walls 241 and 242, are provided mountingframes 250 in which are removably mounted ultrasonic transducers 252,which project high frequency beams of energy across the upper largersection duct horizontally and transversely of the flow 248 of the liquidsuspension through the upper duct section. Thus the particles in thesuspension pumped through the upper portion of the duct are continuouslyexposed as they pass or flow between the partition 245 and top wall 240and two side walls 241 and 242. These transducers 252 are mounted allalong each of the ultrasonic separator units 22 through 26, and areseparated from the duct 240 by flexible vibrating plates mounted in theframes 250. Since these plates are vertical, the accumulation of gasbubbles on them does not occur to cause any piercing or rupture thereof,as would be the case if they were located in the top wall 243 of theduct 240. Furthermore, if they were located in the bottom wall 244 ofthe duct, they could accumulate hydrocarbons which would insulate theirvibrations from the particles flowing through the duct. For example,this particular separator unit or duct 240 may have a width of threefeet, a height or thickness of one foot and a length of about 40 to 50feet. The rectangular frames 250 for the transducers 252 may be abouteight by eighteen inches, and the height of the upper section duct maybe eight inches and that of the lower section duct for accumulation ofthe sediments may be about three and a half inches.

The other parts of the apparatus may be of conventional construction,namely the pumps 16, 20 and 58, as are the piping and valves connectingthem to the other units of the apparatus.

The spray tank 12 may have a tapered bottom and comprise pressurenozzles suspended down in the center of the tank.

The bituminous oil mixing tank 50 may contain the partition 52 so thatas the hydrocarbons or bitumen is collected and mixed with a chemical todecrease its viscosity, the lower viscosity bitumen oil may easily flowover the top edge of the partition 52 into the other portion of the tankfor withdrawal through the pipe 56, through which it may be easilypumped.

The water heater 60 may comprise a tank with a steam coil 62 therein andmay be of any conventional size or shape as may be required, dependingupon the volume of the system and the amount of water to be mixed withthe oil sands or hydrocarbon impregnated particles to be treated and forcarrying these particles through the ultrasonic separator units 22through 26.

C. Examples

A pilot plant sample of five gallons of tar sand tailings from anAlberta tar sand hot water separation process were pumped through arectangular vertical tower duct ultrasonic separator about 14 feet high,one foot wide and eight inches thick, along opposite eight inch sides ofwhich separator tower duct were placed three ultrasonic transducershaving a frequency of 24 kiloHertz. These transducers were staggered twoon one side and one on the other side of the tower on the parallelvertical walls thereof. The water that was mixed with the tailings wasrecirculated from near the top of the tower to the bottom by means of apump and the bitumen that had been coating the sands were skimmed fromthe top of the tower in a heavy bituminous layer. The clean sand wasaccumulated in three baffles below each of the transducers, whichbaffles angularly extended from the insides of the tower up into theupward flow of the suspension. The edge of the baffles caused turbulencein the flow to keep the suspended particles mixed in the water carrierso as to insure all of the particles were contacted several times by thetransverse horizontal vibrations from the ultrasonic transducers. In theV-trough junction of each of these baffles with the vertical walls wasan opening for the withdrawal of the sediment and clean sand thatcollected in these junctions. The duration of the suspension in thetower was about seven minutes and it was found that the lowest bafflejunction collected mostly clean sand, the intermediate baffle junctioncollected clean sand and water, and the upper baffle junction collectedsubstantially no sand and mostly water. The sand and water that wasdrawn from each of the baffle junctions was allowed to settle, and thewater become absolutely clear and the sand was completely free ofhydrocarbon substances and bitumen.

While there is described above the principles of this invention inconnection with specific apparatus, it is to be clearly understood thatthis description is made only by way of example and not as a limitationto the scope of this invention.

I claim:
 1. A continuous process for the separation of hydrocarbons from earth and sand particles containing said hydrocarbons comprising:(A) breaking said particles into a size less than about two centimeters in diameter, (B) suspending said broken particles in water, (C) pumping the suspension of broken particles upwardly through an inclined duct from its lower end, (D) subjecting the suspension of particles in and along said duct to horizontal ultrasonic vibrations ranging in frequency between about 18 and 27 kiloHertz so that each particle is exposed to said vibrations for at least about five minutes to separate substantially all of said hydrocarbons from said earth and sand particles and to entrain the densest of said hydrocarbons with gases from cavitation sufficient to cause said densest hydrocarbons to float on said water to the upper end of said duct, (E) removing said separated earth and sand particles continuously along the lower side of said inclined duct, (F) removing said separated hydrocarbons from the floating layer formed thereof at the upper end of said duct, and (G) recycling said water from below said layer at the upper end of said duct to the broken particles pumped into the bottom of said duct.
 2. A process according to claim 1 wherein said hydrocarbons include bitumen.
 3. A process according to claim 1 wherein said earth and sand particles containing hydrocarbons are tar sands.
 4. A process according to claim 1 wherein said earth and sand particles containing hydrocarbons are tar sand tailings.
 5. A process according to claim 1 wherein said earth and sand particles containing hydrocarbons are oil shale particles.
 6. A process according to claim 1 wherein said particles are broken to a size less than about half a centimeter.
 7. A process according to claim 1 wherein said suspension contains at least 50% water by weight.
 8. A process according to claim 1 wherein said water is heated to a temperature below about 90° C.
 9. A process according to claim 8 wherein said water is heated to a temperature between about 70° and 80° C.
 10. A process according to claim 1 wherein said suspension of particles is exposed to ultrasonic vibrations for between about six and ten minutes.
 11. A continuous process for the separation of hydrocarbons from a mixture of particles containing said hydrocarbons comprising:(A) heating water to a temperature below its boiling point, (B) suspending said particles in said heated water, (C) pumping the suspension of particles upwardly through an inclined duct from its lower end, (D) subjecting the suspension of particles in and along said duct to horizontal ultrasonic vibrations ranging in frequency between about 18 and 27 kiloHertz so that each particle is exposed to said vibrations for at least five minutes to separate substantially all of said hydrocarbons from said particles and to entrain the densest of said hydrocarbons with gases from cavitation sufficient to cause said densest hydrocarbons to float on said water to the upper end of said duct, (E) removing said separated hydrocarbons from the floating layer formed thereof at the upper end of said duct, (F) removing said separated particles continuously from below the level from which said hydrocarbons are removed, and (G) recycling said water from below said layer at the upper end of said duct to the particles pumped into the bottom of said duct. 